From 7347790c9d99e71b342d981cec5110b4177190c2 Mon Sep 17 00:00:00 2001
From: "Tobias S. Josefowitz" <tobij@tobij.de>
Date: Sat, 2 Nov 2019 20:14:57 +0100
Subject: [PATCH] Optimizer: Be more careful when optimizing away assignments
Checking for SCOPE_SCOPED is too agressive, check for SCOPE_SCOPE_USED
instead.
---
CHANGES | 4 ++++
src/peep.in | 4 ++--
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/CHANGES b/CHANGES
index 2ef647fd73..541ba1a720 100644
--- a/CHANGES
+++ b/CHANGES
@@ -91,6 +91,10 @@ o Compiler
- Fixed some corner cases where file names where missing from
backtraces.
+ - Check the proper flag to determine if a local variable may be used
+ before optimizing away certain assignments if the assignment is
+ immediately followed by a return of the variable in question.
+
Crypto.ECC
Now works against Nettle 3.5.
diff --git a/src/peep.in b/src/peep.in
index bb7e5d754e..7c27227e49 100644
--- a/src/peep.in
+++ b/src/peep.in
@@ -216,8 +216,8 @@ ASSIGN_GLOBAL_AND_POP GLOBAL_LVALUE($1a) DEC_AND_POP : ADD_NEG_INT(1) ASSIGN_GLO
GLOBAL_LVALUE INC_AND_POP GLOBAL($1a) : GLOBAL_LVALUE($1a) INC
GLOBAL_LVALUE DEC_AND_POP GLOBAL($1a) : GLOBAL_LVALUE($1a) DEC
-ASSIGN_LOCAL RETURN [!(Pike_compiler->compiler_frame->lexical_scope & SCOPE_SCOPED)]: RETURN
-ASSIGN_LOCAL VOLATILE_RETURN [!(Pike_compiler->compiler_frame->lexical_scope & SCOPE_SCOPED)]: VOLATILE_RETURN
+ASSIGN_LOCAL RETURN [!(Pike_compiler->compiler_frame->lexical_scope & SCOPE_SCOPE_USED)]: RETURN
+ASSIGN_LOCAL VOLATILE_RETURN [!(Pike_compiler->compiler_frame->lexical_scope & SCOPE_SCOPE_USED)]: VOLATILE_RETURN
ASSIGN_LOCAL BRANCH_WHEN_ZERO LOCAL($1a) RETURN LABEL($2a): ASSIGN_LOCAL($1a) RETURN_IF_TRUE LABEL($2a)
ASSIGN_LOCAL BRANCH_WHEN_ZERO LOCAL($1a) VOLATILE_RETURN LABEL($2a): ASSIGN_LOCAL($1a) RETURN_IF_TRUE LABEL($2a)
--
GitLab